Will a 13 or 14 tooth front sprocket improve acceleraton?What do they do for me at the MX track?Thanks!

 

Compared to what? You need to give more details (machine & current gearing) but here's some number I've pulled out of the air.

If your gearing is 13/39 F/R, then adding a 14F will add top speed at the expense of losing bottom end power.

If your gearing is 14/39, then adding a 13F will increase low end power but drop a couple mph on top.

Consequently, it's just the opposite on the rear.

Given the current numbers (13/39), it would take a 3 tooth change in the rear to equal the 1 tooth change on the front.

Here's some formula's

Current gearing at 13/39 equals a ratio of 3:1 (39 divided by 13 equals 3.0)

To increase low end hp the ratio should go higher (ex 13/42 equals 3.23:1) This is also called lowering your gearing even though the numbers go up.

To increase top speed, the ratio should lower (ex 13/36 equals 2.77:1) This is also called raising your gearing even though the numbers go down.

To make a long story longer, if stock tires are 22" and you go down to an 18", you have effectively "lowered" your gearing which gave you more hp low, but a slower top speed.

There now, clear as mud???

 

SORRY TO BREAK IT TO YOU BUT 250X STOCK FRONT SPROCKETS ALREADY HAVE 13 TEETH. IF YOU WANT BETTER ACCELERATION GO DOWN A TOOTH TO A 12, OR UP A TOOTH TO A 39 ON THE BACK SPROCKET IF YOU DONT WANT TO MESS WITH THE FRONT SPROCKET. ADDING MORE TEETH TO THE FRONT OR TAKING AWAY TEETH FROM THE BACK SPROCKET WILL GIVE YOU MORE TOP END AND YOU DONT WANT TOP END ON A TRACK!

IF YOU DONT WANT TO MESS WITH THE SPROCKETS JUST GET SMALLER TIRES. DOING THAT WOULD BE THE SAME THING AS GOING DOWN A TOOTH ON YOUR FRONT SPROCKET(IF YOU GET 20"), BUT MOST PEOPLE THAT RACE TRACK GET 18" WICH DROPS 2 TEETH OFF THE FRONT WICH GIVES YOU A HELL OF AN ACCELERATION! (stock tires are 22")